Manufacture of high-compression automotive distillate



'c. J. PRATT 2, MANUFACTURE OF HIGH COMPRESSIQN AUTOMOTIVE DISTILLATEMarch 25, 1930.

Filed July 13, 1927 )INVENTOR.

Patented Mar. 25, 1930 UNITED STATES PATENT OFFICE cnm'ron JOHN rnnrr,or sr. tours, mssounr OI. HIGH-COMPRESSION A'UTOMOTIVE DISTILLATEApplication filed July 13, 1927. Serial in. 205,288.

apparatus for the conversion of a liquid hy- 1 drocarbon series having agiven fractional gravity distillation range into a liquid hydrocarbonseries having a different fractional gravity distillation range; theprovision of means for converting crude oil, or any fraction madetherefrom into the maximum amount of automotive distillate resemblingthe present United States Motor Specification asoline with the admixtureof not less than orty pprcent (40%) of coal tar benzol; and

the prov1sion of-means of the class described which produces-a minimumamount of residual oil, coke and gas. H 1 v One of the salientobjects'of-the invention is to accomplish the desired conversion atsubstantially atmospheric pressure within the system, therebyeliminating .many undesirablefeatures of previous systems.v

Another object of the invention is to man- I ufacture an automotivedistillate containing the maximum amount of anti-knocklpropertiescommercially obtainable from the hydrocarbons undergoing conversion.Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly comprises the elements and combination ofelements, features of construction, and arrangements of parts which willbe exemplified in the structure hereinafter described, and the scope ofthe application of-which will be indicated in the-following claims.

In the accompanying drawing, in which is illustrated one of variouspossible embodiments of the invention, the figureillustrates"diagrammatically. the relationship between the elementso'f the system.

Corresponding reference characters indi-' cate corresponding partsthroughout the single view of the drawing. 1

Referrin now more articularly to the drawing, t e indicia A ustrates asupply tank containing any liquid hydrocarbon whlch may be crudepetroleum or any trac tion made therefrom. Numeral 1 illustrates easuction line on which is located valve 2 through which the liquidhydrocarbon, hereafter referred .to asoil, is delivered to suc-.

tion side of pump 3. The oil is discharged through line 4: and suchquantity as desired is delivered by a regulatingv valve 5 in line 4 6into a cooling coil 7, located inside a dephlegmator B. The oil passingthrough coil 7 absorbs heat from certain vapors (to'be de-' I scribed)in dephlegmator B and passes from v the dephlegmator to a common headerline j through coil outlet line 8.. I By manipulating the regulatingvalve 9,. any desired quantity of oil may be admitted from pumpdischarge line 4 through line 10 into a cooling coil 11 located in alower oil reservoir section B of the'dephlegmator B.

By regulating a valve 12 in theline 13, any desired quantity of the oilpassing out of coil 11 may be admitted to a'common header to a furnaceheating coil 17. By regulating valve 1.4 an desired quantity of oil maybe returne through-line 15'to supply tank A.

It is to be understood that there is a possibility that an excess amountof oil will necessarily be pumped through coil 11 above the requiredamount to be fed to the system in addition to the oil fed to the systemthrough coil 7. This ,excess amount can be returned direct through line15 to supply tank" A or it could, if desired, be made to pass through acoolin coil before returning to the supply tank y J Line 16 is'a commonheader through which oil is delivered from lines 8 and 13-to heatingcoil 17, located in preheating furnace O. Valve 18 is located at theoutlet 'ofcoil 17 and is used, if necessary, to. prevent the oil beingdeliveredunder substantial pressure through line 19 into the expansionchamber D. The purpose of this is .to prevent pressure from building upin the expansion chamber D.

The vapors from expansion chamber D leave the vessel at a point near thetop through va or line 20, which terminates as a reboiling 001121, nearthe bottom of the upper fractionv ating section S of dephlegmator B. Theob- 1 drawn through line 22 and delivered to .a cooling coil 23,submerged in water contained in cooling box E. A valve 24 at the outletof the cooling coil regulates the liquid level in expansion chamber Dand delivers the desired amount of oil to be withdrawn from the systemthrough line 25 to a suitable storage tank, not shown on the drawing.

It is to be understood that this residual oil may gravitate to storageor may be withdrawn by means of a pump.

Inside the dephlegmator B in the top of the fractionating section S ofthe vessel, located below cooling coil 7 and above the re-boiler coil21, are located a plurality of battle plates 26, which may be of anydesired type to provide intimate contact between liquid and vaporsundergoing treatment.

Numeral 27 illustrates a'diaphra m separating the upper fractionatingsection from the lower oil reservoir section of dephlegmator B. Numeral28 illustrates an overflow nozzle adapted to maintain a liquid level inthe upper fractionating section S. It is to be understood that thisnozzle may extend, if desired, above or into the re-boiler coil 21 (seefor example the dotted lines).

It is to be understood that the dephle mator B may be divided into aplurality of ractionating and reservoir sections, or the dephlegmatormay be composed of several separate fractionating and dephlegmatorsections with proper outside connections to insure the correctfunctioning of the apparatus. In other words, the fractionating sectionS and the reservoir section R may be formed as separate units, properlyinterconnected by suitable lines.

The liquid reservoir section B of dephlegmator B is cooled to anydesired degree above atmospheric b the oil passing through coil 11. Thecoole oil in reservoir B provides the precracked chargin' stock, whichis withdrawn through suction line 29 by means of pump 30 and isdischarged through line 31 to a heating coil 32 of small cross-sectionalarea in a cracking furnace F. Substantially atmospheric pressure is usedin the coil 32; that is, the pressure is'substantially only thatnecessary to overcome the frictional resistance of the coil.

A valve 33 located at the outlet of heating 'coil 32, can he used ifnecessary to prevent cracked oil being'delivered under pressure throughline 34 into a heat exchanger coil 35, located at a point near thebottom of the expansion chamber-D. The object of this exchanger coil 35is to reboil all light distillates from the residual oil in the bottomof expansion chamber and at the Sametime reduce the temperature of theoil entering the expansion chamber from the cracking furnace coil.Anotherpurpose of'this is to prevent coking.

A plurality of bafile plates 36 are placed inside the expansion chamberabove exchangbr coil 35 in order to provide intimate contact between theliquid and vapors discharged through line 19 and the vapors dischargedfrom exchanger '35. It is to be understood that the heavy vaporsdischarged into ex-. pansion cham er from line 19 will absorb a certainamount of the lighter vapors delivered to the expansion chamberconditioner from coil 35.

It can be seen that the vapors from both precracking coils 17 andtreating coil 32 blend and pass out of the expansion chamber 'D throughthe line 20, terminating in coil 21 into fractionating section ofdephlegmator B. It is a function of the fractionating section ofdephlegmator B to separate out the desired fraction of oil vapors forautomotive consumption which leave the dephlegmator through vapor line37 at a point near the top. These vapors pass through condenser coil 38,

submerged in water contained in condenser box G. The condensed vaporsand non-con-' densable gas pass out through line 39 into gas separatorH-on which is located liquid level gauge 40. The non-condensable gas isWithdrawn through line 41 ata point near the top of gas separator H bymeans of pump or blower 42, which discharges the non-condensabl-gasthrough line 43 either to an absorption plant for the further recoveryof automotive distillate or the non-condensable gas.

may be used as fuel, for the furnaces F and C.

By opening valve 4 1 automotive distillatemay be withdrawn from thebottom of gas separator H and delivered to a suitable storage tank (notshown) through line 45. It is to be understood that the automotivedistillate may either gravitate to storage or may be withdrawn by means,of a pump.

Numerals 46 and 16 represent fuel burners of a conventional type, whichsupply the products for combustion to preheating and cracking furnace Cand F, respectively.

Flanged. manholes 47 and 47 on expansion chamber D and flanged manholes48 and 48' on dephlegmator B provide a means of cleaning and repairingthe interior of either vessel.

The charging stock supply tank A will be substantially at atmospherictemperature. The charging stock after passing through the cooling coil 7and 11, enters coil 17 in the preheating furnace at a temperature of theorderof 400 Fahrenheit, which is low enough to' prevent substantialcoking. The temperature of the oil entering the preconditioner throughline' 19 isof the order of 800 Fahrenheit.

'The cooled charging stockfrom the lower reservoir section B ofdephlegmator B entemperature of the order of 250 Fahrenheit and leavesthe cracking coil through line 34 at a temperature above 1100Fahrenheit. The vapors from expansion chamber D admitted to dephlegmatorB through vapor line 20, enters the dephlegmator at a temperature .notto exceed 800 Fahrenheit. The vapors leaving the de-phlegmator 'throughline 37,

when preparing the end-point distillate for the-market should register atemperature of not more than 410 Fahrenheit. The gravity,

rather than the temperature, will determine the'quantity of residuum tobe withdrawn from the expansion chamber through line 22;

' With the proper velocities through the heating coils the aboveconditions will treat the oil in the desired manner without theaccumulation ofan appreciable amount of carbon within the system andwith the production of the least possible amount of non-condensable gas.

The temperature in the preheating furnace C is low enough to preventcoking of the crude oil, which tends to coke at lower temperatures thanthe recycled or precracked stock. Conversely,'. the .precracked stock,

' from which the residuums andIcoke-forming constituents have beenremoved in the expansion chamber D, are subjected to a hightained.

er temperature in the cracking coil 32 without coking therein. Thecrackedvapors from the coil 32 can be brought to a temperature such thatthey will, upon contacting with the films of preheated crudes in thevaporizing chamber D, crack and further vaporize said preheated crudes,leavingas a liquid in said chamber D the residuums and coke-formingconstituents. By the term coke-forming constituents herein is meant such.heavier fractions or residuums or the like of the crude oil or chargingstock as are adapted to coke under the high temperature crackingoperation described. The point is that the crude stock and recycled orpre cracked stock are each made'to pass through regions at differ- Fromthe crudes, there-Y fore, in the vaporizing chamber D is formed enttemperatures.

a recracked stock, devoid of residuums and co :e-forming constituents,which is subsequently subjected to high temperature crack -w ing without0 casioning coke formation in the high tempe ature still or crackingfurnace F.

It will be seen from the above that the above process involves twoheating stages whereby coking is prevented and consequent ly time saved.Furthermore, excessive gas production is prevented by absorption.Another point is that the product is blended hot and in the vapor stage.I

In view of the above, it will be seen that the several objects. of the.invention are achieved and other advantageous results at- As manychanges could be made-incarrying out the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as -illustrative and not in a limitingsense.

I claim:

1. The process of treating hydrocarbons which comprises preheating saidhydrocarbons to a temperature insufficient to coke the heavierconstituents thereof, subjecting said preheated hydrocarbons to intimatecontact with'cracked vapors ofrecycled hydrocarbons whereby saidpreheated hydrocarbons are va-. porized and partially cracked, and thecoke- -forming constituents of said preheated hydrocarbons are removedtherefrom as liquids, comingling the vapors generated from saidpreheated hydrocarbons and said cracked vapors of recycled hydrocarbons,separating said comingled vapors into lighter constituents and heavierconstituents, subjecting said heavier constituents, to a vapor phasecrack:

ing operation in a stream of restricted crosssectional area atsubstantially atmospheric pressure, and recycling said cracked vaporsinto indirect heat-exchange relationship with said heavier, coke-formingconstituents of.

said. preheated original hydrocarbons, and .then nto intimate contactwith said preheated original hydrocarbons.

2. The process of treating hydrocarbonmately contacting the same withcracked oil .vapors to form precracked vapors, partially condensing saidprecracked vapors to a precracked' oil, sub ecting said pre-cracked oilto a vaporphase cracking operation without substantial coke formation,and bringing the cracked vapors into contact with said preheated oil tocrack said preheatedbil, and

removing light cracked hydrocarbon vapors and condensing the same.

3. The process of treating hydrocarbon oils which comprises subjectingsaid hydrocarbon oil to a reliminary cracking operat1on whereby coe-forming constituents are removed therefrom in liquid form, saidcracking operation being conducted at substantially atmosphericpressure, said cracking operation being effected by filming saidhydrocar .bon oil and intimately contacting the same with cracked oilvapors to form precracked vapors, partially condensing theprecrackedvapors to a precracked oil, maintaining said precracked vapors and atleastpart of said p precracked oil in indirect heat-exchange relationship,subjecti ng said precracked oil to 4- mower a vapor phasecracking operation Without substantial coke formation, and bringing thecracked vapors into contact with said hydrocarbon oil to crack saidhydrocarbon oil, and removin 1i ht cracked hydrocarbon vapors and conensmg the same.

In testimony whereof, I have signed' my vname to this specification this11th day of Ju1 ,;92?. I i

GLIFTQN JoHN PRATT.

